import java.util.LinkedList;
import java.util.List;


public class IntegerStack {

	private LinkedList<Integer> listaEnteros;
	
	public IntegerStack() {
		 listaEnteros = new LinkedList<Integer>();
	}
	
	public void push(int i) {	
		listaEnteros.addFirst(i);
	}
	
	public int pop() {
		return listaEnteros.remove();
	}
	
	public int peek() {
		return listaEnteros.get(0);
	}
	
	public boolean isEmpty() {
		return listaEnteros.size() == 0;
	}
}
